Carburetor Noise

Howdy, folks. Thanks for lots of good info over the years, but I finally have to ask a question that hasn't been covered (as far as I can tell).

I have a manual 5-speed 1994 Pick-up with around 150,000 miles on it and no major work done (because no major problems ever came up). Today, out of the blue, the carburetor starts making a sort of squeak in fifth gear. It sounded a bit like something metal scraping the side of the truck and it sounded a bit like when a small rock is caught under the windshield wipers ... that sort of squeak. Not a prolonged, continuous noise, just every once in a while.

I down shifted and nothing, it sounded fine. I shifted back to fifth and the sound had vanished, but then I had to accelerate for a hill and it came back and more often.

I figure it has to be the transmission, because the sound completely disappeared when I took it out of gear and revved the engine, and I figure it has to be fifth gear because it doesn't happen in any other.

Any ideas what this could be or how serious it is?

Worn clutch perhaps????

Is it possible for a worn clutch to only make noises in one gear, but not in another?

A worn clutch is more noticeable ... noise, slipping or whatever... usually in top gear when the vehicle presents the most torque-load to the drive train.

Does pushing the clutch pedal affect the noise?

Yeah, stops it completely, actually, but wouldn't that also happen if it was the tranny?

Possibly, but I'm betting on the clutch. The gears are still being pulled along, (but with no load) when the clutch is engaged.